1. Field of the Invention
The present invention relates to a touch module, and more particularly, to a touch module and a method of fabricating the same.
2. Description of the Prior Art
Display devices with touch panels are getting popular in recent years. Most of touch panels adopt indium tin oxide (ITO) transparent conductive films to form sensing components. However, resistances of the ITO transparent conductive films are too high to serve as sensing components of touch panels of medium or large sizes. Metal mesh, on the other hand, has lower resistances comparing to the ITO films. Such that metal mesh is a better choice to serve as sensing components of touch panels of medium or large sizes.
The touch panel includes a substrate plate and sensing components formed on the substrate plate. A surface of the substrate plate can be defined as a sensing area and a lining area around the sensing area. The sensing components include a sensing line located at the sensing area and a peripheral line located at the lining area. The sensing line is utilized for sensing touches of object. The peripheral line is utilized for receiving signals from the sensing line and transmitting the signals to a sensor to process. There are two methods of fabricating the sensing line and the peripheral line. The first method is to form a physical line on the substrate plate by processes of metal coating and photolithography. The first method has higher cost. The second method comprises: applying an adhesive film on the substrate plate, impressing troughs of patterns relating to the sensing line and the peripheral line on the adhesive film, filling a silver paste in the troughs, and baking it at high temperature. The cured silver paste will form a conductive layer. The conductive layer serves as the sensing line and the peripheral line. The second method has lower cost but also has some drawbacks. For example, a width of the peripheral line needs to be increased to reduce resistance. As a result, an area of the touch panel increases, and that is a disadvantage with regard to the design of narrow bezel. In addition, the peripheral line has to form a grid structure by mesh to fit the sensing line of the sensing area. For safety, the peripheral line needs to include at least four intersections align with a direction along a width of the lining area to prevent the peripheral line from breakage; therefore, the width of the lining area cannot be reduced. The silver paste filled in the troughs is uneven because a width of troughs relating to the peripheral line is different from that relating to the sensing line, and that lead to possibilities of breakage and reduction of yield rate.